Randomised controlled trial of graded exercise in patients with the chronic fatigue syndrome
BMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7095.1647 (Published 07 June 1997) Cite this as: BMJ 1997;314:1647All rapid responses
Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.
From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.
The word limit for letters selected from posted responses remains 300 words.
Apologies: I forgot to include the 95% Confidence Intervals for this
study that Malouff et al[1] calculated: -0.03 to 0.95 (as already stated,
mean for Cohen's d of 0.46) (See Table 1).
Tom Kindlon
[1] Malouff, J. M., et al.: Efficacy of cognitive behavioral therapy
for chronic fatigue syndrome: A meta-analysis. Clinical Psychology Review
(2007), doi:10.1016/j.cpr.2007.10.004
Competing interests:
Assistant Chairperson, Irish ME/CFS Association - for Information, Support & Research (voluntary position)
Competing interests: No competing interests
Given that the objective of this study was to "test the efficacy of a
graded aerobic exercise programme in the chronic fatigue syndrome", some
people might be interested in the size of an effect measure, the cohen's d
value, which has been calculated by Malouff et al[1].
For a meta-analysis of the efficacy of CBT for CFS patients, they
calculated, d, using the following method: "Separate mean effect sizes
were calculated for each category of outcome variable (e.g., fatigue self-
rating) and for each type of outcome variable (mental, physical, and mixed
mental and physical). Studies generally included multiple outcome
measures. For all analyses except those that compared different categories
or types of outcome variables, we used the mean effect size of all the
relevant outcome variables of the study."
The d value for this study (see Table 1) is 0.46. To put this in
some sort of context, the mean effect size Malouff et al found was d=0.48
which they said was "nearly a medium effect size by the standards
suggested by Cohen (1988)". For anyone unfamiliar with Cohen's d values,
they are not bounded by 1; also, the higher the score, the bigger the
"effect size" i.e. the more "effective" a treatment was found to be.
Tom Kindlon
[1] Malouff, J. M., et al., Efficacy of cognitive behavioral therapy
for chronic fatigue syndrome: A meta-analysis. Clinical Psychology Review
(2007), doi:10.1016/j.cpr.2007.10.004
Competing interests:
Assistant Chairperson, Irish ME/CFS Association - for Information, Support & Research (voluntary position)
Competing interests: No competing interests
A more complete set of data from the study would have been useful
I have just read a related paper to this[1]. It involved 66 patients
with CFS without a current psychiatric disorder (from this study), 30
healthy but sedentary controls, and 15 patients with a current major
depressive disorder. Comparisons were made between the various groups.
Regression models were calculated both on the exercise tolerance (time
spent on the treadmill) at the start of trial and also for the exercise
tolerance after three and six months of GET for the CFS patients. It
refers readers regularly back to this paper. However combining the papers
does not give information on many of the outcome measures tested at three
and six months and gives incomplete information on others.
The Fulcher paper (2000) mentions the following measurements - I
thought I would list them to give people an idea what I am talking about:
Age (y), Height (cm), Weight (kg), Body mass index, Total skinfold (mm),
Female:male ratio (%), Test duration (min), Peak oxygen uptake
(ml/kg/min), Maximum ventilation (l/min), Maximum heart rate (beats/min),
Recovery heart rate (beats/min), Predicted maximum heart rate (%),
Submaximal blood lactate (mmol/l), Post-test blood lactate (mmol/l),
Maximum voluntary quadriceps contraction (Newtons), HAD anxiety score, HAD
depression score, Somatic amplification score, PSQI sleep score, Total
fatigue, Mental fatigue, Physical fatigue, Chalder fatigue, SF-36 physical
function, SF-36 role physical, SF-36 bodily pain, SF-36 general health, SF
-36 vitality, SF-36 social function, SF-36 role emotional, SF-36 mental
health. In particular complete information from the results of the
exercise testing would have been useful.
A major trial testing Graded Exercise Therapy (GET) is currently
being undertaken[2]. However, the exercise testing involved is different,
involving just a six-minute walking test and a self-paced step test of
fitness. It would have been interesting to have had all the data from
before and after the intervention in this study to investigate what
actually occurred. Perhaps this can be taken on board for the current
trial[2] given PDW is one of principal investigators, as well as for other
trials in the area.
[1] Fulcher KY, White PD. Strength and physiological response to
exercise in patients with chronic fatigue syndrome. J Neurol Neurosurg
Psychiatry. 2000 Sep;69(3):302-7.
[2] White PD, Sharpe MC, Chalder T, DeCesare JC, Walwyn R; PACE trial
group. Protocol for the PACE trial: a randomised controlled trial of
adaptive pacing, cognitive behaviour therapy, and graded exercise, as
supplements to standardised specialist medical care versus standardised
specialist medical care alone for patients with the chronic fatigue
syndrome/myalgic encephalomyelitis or encephalopathy. BMC Neurol. 2007 Mar
8;7:6.
Competing interests:
None declared
Competing interests: No competing interests